RISAT-1

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Indian Earth observation satellite

title: "RISAT-1" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["spacecraft-launched-in-2012", "earth-observation-satellites-of-india", "space-synthetic-aperture-radar", "2012-in-india", "risat"] description: "Indian Earth observation satellite" topic_path: "geography/india" source: "https://en.wikipedia.org/wiki/RISAT-1" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Indian Earth observation satellite ::

::data[format=table title="Infobox spaceflight"]

Field	Value
name	RISAT-1
names_list	Radar Imaging Satellite-1
image	Render_of_Radar_Imaging_Satellite_RISAT-1_in_deployed_configuration.png
image_caption	Render of RISAT-1 satellite
image_size	300px
mission_type	Earth observation
Radar imaging satellite
operator	ISRO
COSPAR_ID	2012-017A
SATCAT	38248
website	https://www.isro.gov.in/
mission_duration	5 years (planned)
4 years (achieved)
spacecraft_bus	RISAT
manufacturer	Indian Space Research Organisation
launch_mass	1858 kg
power	2.2 kW
launch_date	26 April 2012, 00:17 UTC
launch_rocket	Polar Satellite Launch Vehicle-XL, PSLV-C19
launch_site	Satish Dhawan Space Centre, First Launch Pad (FLP)
launch_contractor	Indian Space Research Organisation
entered_service	19 October 2012
deactivated	31 March 2017
last_contact	30 September 2016
orbit_reference	Geocentric orbit
orbit_regime	Sun-synchronous orbit
orbit_periapsis	539 km
orbit_apoapsis	543 km
orbit_inclination	97.55°
orbit_period	95.49 minutes
orbit_mean_motion	14
apsis	gee
instruments	Synthetic-aperture radar (C-band) (SAR-C)
programme	Earth observation satellites series
previous_mission	Resourcesat-2
next_mission	SARAL
::

| launch_date = 26 April 2012, 00:17 UTC | launch_rocket = Polar Satellite Launch Vehicle-XL, PSLV-C19 | launch_site = Satish Dhawan Space Centre, First Launch Pad (FLP) | launch_contractor = Indian Space Research Organisation

| entered_service = 19 October 2012 | disposal_type = | deactivated = 31 March 2017 | last_contact = 30 September 2016

| instruments = Synthetic-aperture radar (C-band) (SAR-C)

| programme = Earth observation satellites series | previous_mission = Resourcesat-2 | next_mission = SARAL

Radar Imaging Satellite 1 or RISAT-1, was an Indian remote sensing satellite built and operated by the Indian Space Research Organisation (ISRO). The second RISAT satellite to be launched, it used a C-band 5.35 GHz synthetic-aperture radar (SAR) for Earth observation.

The launch of RISAT-1 came several years after that of RISAT-2, which carried an Israeli-built X-band radar. The RISAT-2 mission was prioritised over RISAT-1 following the 2008 Mumbai attacks, resulting in RISAT-1 being delayed by several years.

Satellite description

RISAT-1 had a mass at liftoff of 1858 kg, making it the heaviest Earth observation satellite to be launched by India, and the heaviest satellite to be launched using a Polar Satellite Launch Vehicle. It had the capability to take images of Earth during day and night, as well as in cloudy conditions.

The satellite is equipped with a 160 × 4 Mbit/s data handling system, 50 Newton-metre-second reaction wheels, and a phased array antenna with dual polarisation.

The mission has an approximate cost of ;the spacecraft itself cost to develop, and a further to launch. The satellite had a design life of five years.

The satellite was used for natural resources management, primarily agriculture planning and forestry surveys, as well as to predict and prevent flooding. It was used for monitoring paddy plantations and yields in the kharif season and to assist India's food security planning. Pictures from RISAT-1 was used to estimate the number of hectares being farmed in India, to assess crop health and predict total yield. It was also used to identify wreckage from aircraft that crashed in forested areas. RISAT-1 was not designed as a surveillance satellite, given its reliance on the C-band.

Instrument

Its synthetic-aperture radar (SAR-C) has a resolution of 3 m to 50 m. It also supports a spotlight mode for prolonged focus on a given geographical area at a resolution of 1 m.

Mission history

Launch

RISAT-1 was launched at 00:17 UTC (05:47 IST) on 26 April 2012 by a Polar Satellite Launch Vehicle, flight number C19, flying in the XL configuration with extended length solid strap-on boosters. The launch, which was the third flight of the PSLV-XL configuration, took place from the First Launch Pad of the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh. The launch marked the twenty-first flight of the PSLV, and its nineteenth successful launch.

After launch RISAT-1 was placed in 470 x 480 km orbit with near 97° inclination. In next two days, RISAT-1 raised its orbital altitude using on-board propulsion to place itself into its operational Sun-synchronous orbit of 536 km with 06:00 Local Time of Equator Crossing. The satellite began its normal operations with a repetitive cycle of 25 days.

Incidents

On 30 September 2016, Joint Space Operations Center identified a debris generating event near RISAT-1. The event created 16 pieces out of which 15 decayed and one was catalogued on 6 October 2016 under NORAD ID: 41797 and COSPAR ID: 2012-017C and decayed on 12 October 2016. Cause of this event was not officially declared but could be related to power system of satellite. A month later on 3 November 2016, RISAT-1 data was declared unavailable on ESA's Copernicus Space Component Data Access portal due to satellite outage. Satellite was experiencing anomalies but ISRO denied they were related to fragmentation event.

End of mission

On 26 July 2017, Department of Space released names of its operational satellites in a reply to a Parliamentary query and RISAT-1 was not included in the list. Later in Annual Report 2017–18 of Department of Space, RISAT-1 was declared non-operational.

References

(26 April 2012). "RISAT-1 satellite launch a "grand success"". The Hindu.
(9 May 2021). "RISAT-1 (Radar Imaging Satellite-1) - Status Mission". ESA Earth Observation Portal.
Raj, N. Gopal. (25 April 2012). "RISAT-1's radar can see through clouds and work in darkness". The Hindu.
Laxman, Srinivas. (26 April 2012). "ISRO Launches India's First Radar Imaging Satellite, RISAT-1". Asian Scientist.
"India to Launch RISAT-2". ASM.
(7 November 2008). "ISRO's New Satellite Could See Through Even Cloudy Sky". Indo Daily.
(26 April 2012). "The importance of RISAT-1". Press Information Bureau, Mumbai.
(26 April 2012). "India successfully launches first microwave radar imaging satellite RISAT–1". The Times of India.
"Earth Observation System". ISRO.
Varma, M. Dinesh. (26 April 2012). "PSLV-C19 puts RISAT-1 in orbit". The Hindu.
"RISAT-1".
"Radar Imaging Satellite (RISAT-1) successfully placed in its final orbit". ISRO.
"Debris-causing event ID'd near RISAT-1 (#38248) on 30 September 2016".
"NASA Orbital Debris Quarterly News, Volume 20, Issue 4, October 2016".
Krishnan, Raghu. (2018-05-09). "It will take 3 years for industry to absorb satellite tech: K Sivan, ISRO chairman". The Economic Times.
"Risat-1 satellite is functioning normally, says ISRO".
"RISAT-1 unavailability". ESA.
(26 July 2017). "Details of satellites being operated by the country at present".
(26 July 2017). "Details of satellites being operated by the country".
"Annual Report Department of Space 2017-18". Department of Space, Government of India.

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